<h2>Problem 259</h2>
<div style="color:#666;font-size:80%;">10 October 2009</div><br />
<div class="problem_content">
<p>A positive integer will be called <i>reachable</i> if it can result from an arithmetic expression obeying the following rules:</p>

<ul>
<li>Uses the digits 1 through 9, in that order and exactly once each.</li>
<li>Any successive digits can be concatenated (for example, using the digits 2, 3 and 4 we obtain the number 234).</li>
<li>Only the four usual binary arithmetic operations (addition, subtraction, multiplication and division) are allowed.</li>
<li>Each operation can be used any number of times, or not at all.</li>
<li><dfn title='A minus sign applied to a single operand (as opposed to a subtraction operator between two operands)'>Unary minus</dfn> is not allowed.</li>
<li>Any number of (possibly nested) parentheses may be used to define the order of operations.</li>
</ul>

<p>For example, 42 is reachable, since (1/23) * ((4*5)-6) * (78-9) = 42.</p>

<p>What is the sum of all positive reachable integers?</p>
</div><br />
